1. Field of the Invention
The present invention relates to a stripe-type organic electroluminescence (EL) panel which comprises at least three kinds of pixels, in which the pixels, each including an organic EL element for emitting light of a particular color, are arranged in a matrix such that pixels for emitting the same color light are arranged in a column.
2. Description of the Related Art
Organic electroluminescence (hereinafter referred to as EL) panels have been receiving attention as one of the next generation flat displays to take place the liquid crystal displays. In the display panels (hereinafter referred to as an organic EL panel), the color of light emitted by each pixel can be determined depending on the kind of light emitting material used to form an organic light emitting layer for the pixel. Thus, pixels for different color light are formed so that RGB display can be realized.
In this organic EL panel, bright display is achieved by increasing the amount of current supplied to each organic EL element. However, increase of a current amount results in reduction of the service life of an organic EL element. Therefore, instead of increasing a current amount, it is desired to ensure the largest possible area for a light emitting region, or an aperture ratio, in each pixel.
A larger aperture ratio enables brighter display while suppressing current supplied to the organic EL element to a relatively small amount (See Japanese Patent Laid-open Publication No. 2001-290441). Increase of an aperture ratio means increase of the proportion of the light emitting region of an organic EL element relative to the entire area of each pixel.
Here, in an organic EL panel of an active type, at least two TFTs are provided in each pixel to drive the concerned organic EL element. Moreover, a data line for supplying luminance data to each pixel and a power supply line for supplying driving current to the organic EL element of each pixel are provided in a column direction, while a selection line (gate line) for selecting a pixel is provided in the row direction. Therefore, the areas where these wirings are placed are not available for use as a light emitting region.
Further, each pixel is provided with a selection TFT, to be turned on or off by the selection line, for supplying a voltage at the data line to a holding capacitor, and a driving TFT for supplying a driving current according to the voltage held at the holding capacitor, from the power supply line to the organic EL element. Therefore, the areas where the TFTs are placed are also not available for use as a light emitting region.
This limitation of an area available for a light emitting region leads to a problem of a reduced aperture ratio.